To me, PSG is not a bad destination for Osimhen. Mbappe will most likely leave at the end of the season and that would make Osimhen the point man for PSG. He will score a lot of goals and win trophies thereby increasing his market value and cementing his name as a top striker in Europe.

Chelsea is another club that has shown interest in Osimhen. Going to Chelsea will be a bad decision. Chelsea are currently struggling and they don't have the players to feed Osimhen properly.

Aside from PSG, another club I think would be good for Osimhen is Arsenal. The kind of football Arsenal plays will favor Osimhen.
Arsenal play from both flanks and also from the middle. One thing strikers love is getting so much support from the flanks and the midfield. That means he's covered. All he needs to do is position properly and be able to build up play with the midfielders and wingers.